At exactly noon on this day in 1883, American and Canadian railroads began using four continental time zones to end the confusion of dealing with thousands of local times.
The need for continental time zones stemmed directly from the problems of moving passengers and freight over the thousands of miles of rail line that covered North America by the 1880's. Most towns in the U.S. had their own local time, generally based on "high noon", or the time when the sun was at its highest point in the sky. The time differences were a scheduling nightmare.
Rather than turning to the federal governments of the United States and Canada to create a North American system of time zones, the powerful railroad companies took it upon themselves to create a new time code system. The companies agreed to divide the continent into four time zones; the dividing lines adopted were very close to the ones we still use today.